Biology Study Set: Micro Week 2 Terms & Definitions

When did Cyanobacteria eveolve?

3 billion years ago

What are the names and shapes of bacteria?

Cocci - sphere shaped

Bacilli - rod shaped

Spirilli - spiral shaped

vibrio - comma shaped

What is the largest bacterial phyla?

B12 preoteobacteria

What bacterial phyla contains gram positive bacteria?

B13 Firmicutes

Where does crystal violet bind to?

Peptidoglycans

Why do we need to stain bacteria?

Staining bacteria adds color to the cells which makes them easier to see using a microscope. The stain is a dye that binds to a cellular structure and provide contrast so that the bacteria appear as colored object against a clear background.

What is the difference between gram negative and gram positive bacteria?

Gram negative bacteria have an inner and outer cell membrane while gram positive bacteria only have one cell membrane and more peptidoglycans on their surface

What is the function and purpose of peptidoglycans in bacterial cell walls?

- Provide shape

- withstand turgor pressure

What is a peptidoglycan made out of?

- Protein

- Polysaccharide

- Chains of alternating polysaccharide (NAG and NAM) crosslinked with peptides (DAP)

What connects peptidoglycan polysaccharides in gram positive bacteria?

Pentaglycine bridge

What connects peptidoglycan polysaccharides in gram negative bacteria?

m-DAP

What is the enzyme that cross links peptidoglycan chains?

Transpeptidases

Where do peptides bind on the peptidoglycans?

NAM

What is implied by transpeptidases being penicillin-binding proteins?

Penicillin is able to bind to these proteins and disrupt the structure of these bacteria

What are teichoic and lipoteichoic acids responsible for?

Attachment to mucosal surfaces

What can teichoic and lipteichoic acids do?

Induce septic shock by inducing IL-1 and TNF-a production in macrophages

What type of bacteria have teichoic and lipteichoic acid?

Gram positive

What is murein?

Peptidoglycan

What is in the periplasmic space of a bacteria?

-Proteases

-Phosphatases

-lipases

-nucleases

All enzymes relating to metabolism

Besides digestive enyzmes, what else does the periplasmic space of a bacteria contain?

Virulence factors such as collegenases and hyaluronidases which aid in infection of the host

What is the outer leaflet is composed primarily of?

Lipopolysaccharide (LPS)

What are the segments of a lipopolysaccharide?

- Lipid A

- Core polysaccharide (sugars)

- O antigen (sugars)

What is the function of Lipid A in a lipopolysaccharide?

Responsible for endotoxin activity due to the 2 phosphate grounds on either side

Proteins known as ______ mediate the diffusion of hydrophilic molecules less than 700 Da in size through the external membrane of a gram negative bacteria.

Porins

What are the two types of secretion systems that gram negative bacteria have?

Sec-dependent

Sec-independent

What are examples of Sec-dependent systems?

Type II and Type V

What are example of Sec-independent systems?

Type I, III, and IV

What secretion systems microinject exotoxins into host cells?

Sec-independent Type III and IV

What is the bacterial capsule?

Gelatinous layer composed of polysachharides that mediates attachment

T or F

The capsule can be considered a virulence factor of bacteria.

True; the capsule can help bacteria escape phagocytosis

What structure plays an important role in the pathogenesis of UTIs by E. coli?

Flagella

How are salmonella species indentified?

By their flagella

Describe a flagella

Helical-shaped filament attached to a hook and an anchor that propels the flagella around to move the cell via locomotion

T or F

Bacteria may organize their cytoplasm into membraneless organelles.

True

What are pili?

Little hair like projections that mediate attachment

Do bacteria have a cytoskeleton?

Yes

When are endospores formed?

when essential nutrients are depleted

What is catabolism?

breaking down molecules

What are metabolites converted into in bacteria?

Pyruvic acid

How do molecules enter bacteria cells?

Through porins on the outer membrane then through diffusion or transporter proteins through the inner membrane

What are the three metabolic pathways bacteria use for metabolizing glucose?

- Glycolytic

- Tricarboxylic acid cycle

- Pentose Phosphate pathway

T or F

In glycolysis, every reaction is facilitated by an enzyme

True

What molecules are needed to start the glycolysis pathway?

Glucose and ATP

What is the product of glycolysis?

Pyruvate

Where does pyruvate go after it leaves glycolysis?

Krebs cycle

What is pyruvate converted to in the kreb's cycle?

CO2, NADH, FADH2, and ATP

What is made in the pentose phosphate pathway?

Necessary precursors of RNA (ribose-5-phosphate) and NADH

What is the last step of metabolism in bacteria?

Electron transport chain which generates ATP through the ATPase and an ion gradient

What is the electron acceptor in the ETC?

Oxygen

Describe obligate anaerobes

Organisms that cannot grow in the presence of O2

Describe obligate aerobes

Organisms that cannot grow without O2 (need oxygen)

Describe facultative anaerobes

Grow in the presence or absence of oxygen

What was the basis of the "Transforming principle" that was established from the Fredrick Griffin mouse experiment?

When dead bad bacteria and alive good bacteria were mixed, the good bacteria were able to become bad. There was a transformation of the good bacteria into bad bacteria

What enzyme binds nucleotides together?

DNA polymerase III

Who discovered semi-conservative DNA replication?

Meselson and Stahl

What is the leading strand?

The strand where replication moves towards the replication fork (follows helicase) 5'-3'w

What is the lagging strand?

The strand where DNA replication moves away from the replication fork; short fragments are synthesized called okazaki fragments

What enzyme makes primer for the DNA during replication?

Primase

What enzyme join okazaki fragments?

DNA ligase

What enzyme replaces RNA primer with DNA?

DNA polymerase I

Describe inducible vs repressible genes.

Inducible genes mean that the presence of something causes their expression. Repressible genes means that the presence of something causes them to cease being expressed

What is one easy example of a repressible gene?

Lac operon; in the presence of lactose the lac operon is expressed however when there is no lactose present the operon is repressed and transcription stops

What are the 3 types of bacteria gene exchange?

- Transformation

- Transduction

- Conjugation

What is transformation (bacteria)?

genes transferred from one bacterium to another as "naked" DNA

What is transduction (bacteria)?

DNA is transferred from a donor cell to a recipient via a bacteriophage

What is conjugation?

A process in which 2 organisms exchange genetic material through a sex pilus

During cell division, what proteins help control the septum formation?

FTsZ and MreB

Which bacteria form spores?

Gram positive

T or F

Bacteria only have a single loop of DNA

True